Dual-Affinity Interphase Engineering Enables Stable Aqueous Zn-S Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous Zn-S batteries are promising for grid storage but face challenges like capacity fade and slow kinetics.
• Existing methods struggle to prevent ZnS decomposition, a key cause of capacity loss.

Purpose of the Study:

• To design a cathode/electrolyte interphase (CEI) that enhances redox reversibility and stability in aqueous Zn-S batteries.
• To address capacity attenuation caused by ZnS decomposition using a dual-affinity interphase.

Main Methods:

• Development of a nano-copper-based CEI with dual affinity for sulfur and ZnS.
• Investigating the CEI's effect on S-S and Zn-S bond dynamics and ZnS stability.
• Electrochemical testing to evaluate cycling stability, capacity, and voltage hysteresis.

Main Results:

• The Cu CEI effectively stabilizes ZnS by minimizing water contact and preventing decomposition.
• Enhanced S-S bond cleavage and weakened Zn-S bonds led to a higher discharge voltage (0.75 V) and reduced activation energy.
• The system demonstrated excellent cycling stability (>1000 cycles) and high areal capacity (~6.5 mAh cm⁻²).

Conclusions:

• The rationally designed Cu CEI with dual-affinity is a viable strategy for high-performance aqueous Zn-S batteries.
• This interphase design significantly improves cycling stability and capacity retention.
• The findings highlight the potential for advanced interphase engineering in next-generation energy storage systems.